In an RFID system and an NFC system which are widely used these days, in order to perform communication between a communication terminal apparatus, such as a cellular phone terminal, and a reader/writer or between communication terminal apparatuses, antennas used for performing communication are individually mounted on the apparatuses. Among these antennas, an antenna mounted on a communication terminal apparatus is disclosed in Japanese Unexamined Patent Application Publication No. 2002-325013 (Patent Document 1).
FIG. 7 shows views of the configuration of an antenna device disclosed in Patent Document 1, which are represented for easy comparison with the embodiments according to present disclosure. FIG. 7(A) is a plan view of the antenna device, and FIG. 7(B) is a sectional view taken along line A-A of FIG. 7(A).
The antenna device shown in FIGS. 7(A) and 7(B) includes a flexible substrate 10, a coil 13 formed on the flexible substrate 10 and constituted by spiral conductor lines having a conductor opening at the center of the wound coil, and a magnetic core 30. A slit 23 is formed in the conductor opening of the flexible substrate 10, and the magnetic core 30 is inserted into the slit 23. A connecting portion 13t is formed at each of an inner peripheral end and an outer peripheral end. This antenna device is arranged above a metallic body 40.